Plated metal body and method of producing same



Patented 1 Jan. 31, 1933 UNITED STATES EMIL 'rnnrsz, or nnnarns'r, HUNGARY, ASSIGNOR 'ro novnsfinr IzzoLmrA Es mosses: RESZVENYTARSASAY, or UJ-IPEST, HUNGARY PATENT OFFICE VILLA- rm'rnn METAL BODY AND mn'rnonor raonuc'me sum in; Drawing. Application filed September 5, 1930, Serial No. 479,923, and in Hungary December 28, 1929.

My invention refers to the plating of metal and more especially to the As is well known to those skilled in the art tungsten bronzes and molybdenum bronzes are compounds which were hitherto produced by reducing acid tungstates and acid molybdates. respectively, at high temperature. It is thus possible to produce for instance barium tungsten bronze BaW O or sodium molybdenum bronze Na Mo O More detailed descriptions of these compounds can be found in. many text books,for instance in Smithells Tungsten (London 38-39, where tungsten bronzes are defined as havin the constitution R OWO2nl/VO wherein R is an alkali-forming or an alkaline earth or similar metal, while 01. is an integer. Thus tungsten and molybdenum bronzes can be defined by the formula R OXO nXO,, wherein X is tungsten or molybdenum.

According to the present invention coatings consisting of these and similar bronzes can be produced in a simple manner on any metallic body. According to the invention the metal body to be coated or plated is placed in a suitable solution of a tungsten or molybdenum compound and inserted in an electric circuit as cathode, whereupon the so= lution is subjected to electrolysis. According to the experiences hitherto made the electrolizing of solutions of normal orthotungstates 'or orthomolybdates.results in the production of tungstenoxides or molybdenum oxides of a low stage of oxidation. Thus for instance, when subjectin to electrolytical decomposition a solution, slightly acidulated with sulfuric acid or hydrochloric acid, of sodium orthomolybdate Na' MoO there is separated out at the cathode a molybdenum oxide Mo O +aqu.

I have now found that if a metal body is inserted as a cathode in a solution of a salt of metaor polytungstic acid or meta--or polymolybdic acid, electrolytic decomposi- 1on will result in the formation of tungsten roduction on metal bases of coatings consisting of com-' ings of different thicknesses can be bronzes or molybdenum bronzes. By suitably selecting and maintaining the conditions of operation, such as for instance the temperature and concentration of the solution and the cathodic current density, the electrolyti-,

cal process can be conducted in such manner that the bronzes obtained are precipitated on the metal body forming the cathode in the form of a firmly adhering and altogether uniform coating.

This coating can be produced with particular advantage from solutions of the alkali metal salts and alkaline earth metal salts of meta-or polytungstic acid or metaor polylnolybdic acid. I prefer using watery solutions of barium meta-tungstate BaW O +9HO or strontium. meta-tun state SrW O +9H O. By simultaneousfy varying the concentration of the solutions and thecathodic current density bronze coatproduced in the same period of time.

In practising my invention I may for in- A stance proceed as follows:

' Example 1 A metal body which may for instance have a surfacearea of 100 mm is placed in a 70% solution of barium meta-tungstateheated to C. and inserted as cathode in an electrolytic circuit comprising an anode consisting of a. precious metal. I now apply to the electrodes -a.voltage such that the intensity of the current flowing through the solution corresponds to vD,'.=1O0 milli amp. per cm of cathodic current. In the present example the electrolytical process is carried through with acurrent of 0,.1 amp. The electrolytical process results in the almost immediate formation of a blue coherent bronze coating. The metal body is now removed from the solution, rinsed with hot water and dried. I

- Emample 2 The metal body to be coated is placed in r of 1-2 milli amp. per cm, any desired metal body forming the cathode. There results a gradually thickening blue coating of barium molybdenum bronze. ."After the lapse of about 3 minutes the circuit is interrupted, the metal body is withdrawn, washed with distilled water and dried.

The solution from which the barium molybdenum bronze is precipitated can be produced for instance in the following manner: a watery sodium meta molybdate solution is treated with a solution of BaCl to produce the corresponding barium meta molybdate, which is then suspended in distilled water, dilute hydrochloric acid being added until the barium meta molybdate has been dissolved.

E wample 3 The metal body to be coated'is placed in a solution of strontium meta-tungstate having a specific density of 1, l and inserted as cathode in the electrolytic circuit, any desired metal body, for instance a piece of tungsten, being used as anode. At ordinary temperature a current corresponding to a cathodic current density of 250 milli amp. per cm is allowed to flow through the solution. As soon as a layerof the desired thickness has been deposited on the metal cathodethe current is interrupted, the metal body withdrawn, washed with hot water and dried.

I may also use mixtures of the different salts.

The new method thus allows plating metal bodies of all descriptions, for instance bodies consisting of tungsten, molybdenum, platinum or nickel with one of these bronzes. Owing to their advantageous properties the metal bodies plated in this manner are particularly adapted for the production of oxide cathodes.

Various changes may be made in the details disclosed in the foregoing specification without departing from the invention or sacrificing the advantages thereof.

I claim 1. As a new product a metal body electroplated with a compound having the formula R OXO nXO wherein X is tungsten or molybdenum, while B is an'alkali-forming or an alkaline earth or similar metal and n is an integer.

2. As a new product a metal body electroplated with a compound having the formula RgOWOmWO wherein R is an alkaliforming or an alkaline earth or similar metal and n is an integer.

3. As a new product a metal body electroplated with a compound having the formula R OMoO nMoo wherein R is an alkaliforming or an alkaline earth or similar metal and n is an integer.

4. As a new product a metal body electroplated with a compound, having the formula BaOVVOmWO wherein n is an integer.

- 5. As a new product a metal body electroplated with a compound having the formula BaM0O nMoO wherein n is an integer.

6. As a new product a metal body electrolated with a.compound having the formula rOWO nVVO wherein n is an integer.

7 The method of plating metal bodies comprising placing the body to be plated in a solution of a salt ofthe group of acids constituted by metaor poly-tungstic and bodybdic acids, inserting said body as cathode in an electric circuit and causing an electric current to act on the solution.

8. The method of plating metal bodies comprising placing the body to be plated in a solution of an alkali metal salt of the group of acids constituted by metaor poly-tungstic and molybdic acids, inserting sald body as cathode in an electric circuit and causing an electric current to act on the solution.

9. The method of plating metal bodies comprising placing the body to be plated in a solution of an alkaline earth metal salt of the group of acids constituted by metaor EMIL "IHEISZ.

CERTIFICATE OF CORRECTION.

Patent No. 1,896,022. 7 Januaryw31, 1933,

' emu, 'nnz sz.

It is hereby certified that the last word of the firm name of the assignee in ithe above numbered patent was erroneously described and specified as "Re'szvenyt'arsasay" whereas said'last word should have been described and specified as "Reszve'nytarsasa'g", as shown by the records of assignments in this office;. and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 16th day of May. A. D. 1933.

M. J. Moore.

(Seal) w t Acting Commissioner of Patents, 

